The pillow is too low, the head and neck is bound to tilt back excessively. The pillow is too high. Excessive forward flexion of the head and neck. Too high, too hard, too short, too narrow, filling inappropriate pillow is not suitable pillow. Suitable for human physiological condition of the pillow should have the following characteristics: head and neck and pillow contact surface is larger, the weight support is more even, the pressure dispersion is also uniform, the muscles around the spine to get full relaxation, and the shoulder blood flow does not cause compression damage; curve shape in line with the cervical spine physiological bending; pillow core can support the whole section of the cervical spine, so that the neck muscle to get full relaxation and rest; pillow core breathability is good, to avoid due to Humidity and aggravate the neck discomfort; pillow size, hardness appropriate; supine pillow height about a fist (according to the individual’s own fist), side lying pillow height should be a fist plus two fingers, habitual side lying pillow height to the midpoint of the spinous process to the distance of the lateral edge of the shoulder peak is appropriate.